Grinding wheel truing apparatus



Nov. 17, 1953 o. E. HILL GRINDING WHEEL TRUING APPARATUS 4 Sheets-Sheet1 Filed May 8, 1951 OIVA E. H/LL qq F78 Ill/eater fiacork' y Nov. 17,1953 O. E. HILL GRINDING WHEEL TRUING APPARATUS Filed May 8 1951 4Sheets-Sheet 2 O/vA E. HILL Nov. 17, 1953 O, E, H 2,659,358

GRINDING WHEEL TRUING APPARATUS Filed May 8, 1951 4 SheetsSheet 5 22 asH IZG , hill/altar IE7 OIVA E. HILL I53 I32 57% L -ELLM Nov. 17, 1953 o.E. HILL 2,659,358

GRINDING WHEEL TRUING APPARATUS Filed May 8, 1951 4 Sheets-Sheet 4Patented Nov. 17, 1953 GRINDING WHEEL TRUING APPARATUS Oiva E. Hill,West Boylston, Mass, assignor to Norton Company, Worcester, Mass, atcorporation of Massachusetts Application May 8, 1951, Serial No. 225,199

5 Claims.

The invention relatesto a grinding-wheel trulug-apparatus, and moreparticularly to a truing apparatus for truing a. formed face on theperiphery of a grinding-wheel. The present invention relates toamodifiedform of the truin apparatus disclosed-in my copendingapplication, Serial sNo." 183,775, J filed September 8, 1950.

One :object of ---the invention is to provide a simple-and thoroughly.practical truing apparatus for:truin mnrirregular shape. on theperiphery of the grindingwheelhaving for example spaced portions .of;difierent .-diametersand an irregular surface therebetween: Anotherobject is to provideanphydraulically-actuatedelectrically-controlled:=truinglapparatussuccessively to true the periphery-of a" grindingrwheel having spacedportions, of ;difierent diameters; andan-irregular surfacetherebetween.:, Another object ofthe inventiorris- ;.to provide-a truingapparatus .with an hydraulically-actuated .cam, {mechanism automaticallytog position: the; truing; tool 1successivelyv to true. multiplediameters on ;a single grinding wheel-anda formed facetherebetween.Another object is 1; to provide. an hydraulically operated traversemechanismior atruing tool and an hydraulically operatedcam mechanismactuated in timedrelation therewith successively to position the truingtool for truing portions of the periphery of the wheel to betrued.Another object is to provide an hydraulically operated cam controlmechanism in; timed relation with; the traversing movement ofthetruingtool; to position the truing tool to true spaced-portions oivarying diameters combined with a master camanda follower for generatingan irregular; formed face therebetween. Other objects will beinpa-rtobvious or in part pointed out hereinafter.

The invention accordinglyrconsists in the features of construction,combinations of elements, and arrangementsyof parts as willbeexemplified in the structure to be hereinafter described, and thescopeof the application of-whiqh .Will be indicated in the following claims.

In the accompanying drawings, -in which is shown one of various possibleembodiments of the mechanical'features of this invention,

Fig. 1 ,is, a front elevation of Y the improved formed .wheel truingapparatus;

Fig. 2 is'aplanzview'of the truing; apparatus;

Fig. 3 is, a verticalsectional view,-;tak en approximately. on, the,line i 3, 3 of, Fig. 1, through the truing. apparatus;

4 is .a horizontal sectional-view, taken approximately on the line 4--4oflFig, 1;

-1 i aecombined draulic and electrical diagram of the controlandactuating mechanism for the truing apparatus;

Fig. 6 is a fragmentary diagrammatic view showing the positions of theparts as the truing too traverses toward the right; and

Fig. '7 is a, similar fragmentary diagrammatic view showing thepositions of the parts as a iurther traversing movement of the truingtool toward the right. The truing apparatus has been illustrated-in thedrawings as applied to a grinding machinehaving a rotatable grindingwheel H! which is partially surrounded by a wheel guard H. The grindingwheel I!) may be a single grinding wheel as shown in Fig.- 1, or ifdesired may be a plurality of adjacent grinding wheels having aperipheral formed face thereonto be trued.; The wheel guard H serves-asa support for an up wardly extending bracket [2. The bracket 12 supportsa slide base l3 which is fixedly mounted thereon by-a plurality ofscrews |4.- Theslide base l3 isprovided with a dovetailed slideway 15 jwhich mates with a correspondingly V shaped dovetailed slideway on alongitudinally movable slide IS. The slide IBis arranged to traverselongitudinally in a direction parallel to the axis of rotation of thegrinding wheel II]. An hydraulically operated mechanism is provided fortraversing the slide [6 longitudinally comprising an hydraulic cylinderI l which is formed integral with the slide base l3. The cylinder [1contains a slidably mounted piston 18 mounted on one end of a piston rodI9. the piston rod I 9 is fastened to a bracket 20 formed integral withthe longitudinally movable" slide it. When fluid under pressure ispassed through a pipe 2| into a cylinder chamber 22 '(Fig. 5), thepiston l8 together with the slide 15 will be moved longitudinally towardtheright. During this movement of the piston 18, fluid within a cylinderchamber 23 may exhaust through a pipe 24. A suitable fluid pressuresystem and a control mechanism therefor for supplying fluid underpressure to the cylinder I! will be hereinafter described.

The longitudinally movable slide l6 serves as a support for atransversely movable vertically arranged sleeve 25. The sleeve 25 ispreferably square in cross section as indicated in Fig. 4. The sleeve 25is provided with a central aperture for supporting a vertically movablespindle -26. The spindle 25 supports a truing tool holder 27 at itslower end. The truing tool holder 21 is provided-with a diamond ortruing tool 28 which is arranged to true the periphery of the The otherendof 3 grinding wheel H] as will be hereinafter described.

The sleeve 25 is provided with a pair of vertically extending ribs orslides 33 and 3| which serve as guides for controlling the verticalmovement of the sleeve 25. A plurality of rollers 32, 33, 34 and 35(Fig. 4) are mounted on studs 36, 31, 38 and 39 respectively. Therollers 32, 33, 34 and 35 are arranged to engage the opposite faces ofthe slides 33 and 3| to support the sleeve 25 having free verticalsliding movement. The studs 31 and 39 are preferably provided witheccentric portions for supporting the rollers 33 and 35 to facilitate atransverse adjustment of the rollers so as to take up lost motionbetween the sliding parts. A similar set of rollers (not shown) areprovided for supporting the lower end of the slides 30 and 3|.

Similarly a plurality of rollers 49, 4|, 42 and 43 are provided forengaging the opposed side faces of the slides 30 and 3|. These rollersare rotatably supported on studs 44, 45, 46 and 41 respectively. Thestuds 45 and G1 are preferably provided with eccentric portions forsupporting the rollers 4| and 43 to facilitate a transverse adjustmentof the rollers to take up backlash between the sliding parts. It willthus be seen that an. anti-friction sliding support has been providedfor the sleeve 25 so that it may be freely moved'in a vertical directionto carry the truing tool 28 in'the desired and predetermined path totrue a predeterminedshape on the periphery of the grinding wheel ID.

A suitable adjusting mechanism is provided for adjusting the spindle 26relative to the sleeve 25 to facilitate either a manual adjustment ofthe truing tool or diamond 28 or an automatic feeding movement thereofduring a truing operation. The upper end of the sleeve 25 is providedwith an integral flange B which serves as a support for a bracket 5|.The upper end of the spindle 26 is provided with a screw thread 53 whichmeshes with a surrounding nut 55. The nut 54 is rotatably supported onthe flanged portion 50 of the sleeve 25. A gear '55 is keyed to the nut54. -The'gear 55 meshes with a pinion 56 mounted on the upper end of avertically arranged rotatable shaft 51. The shaft 57 is rotatablymounted within the bracket 5| and is provided at its lower end with amanually operable hand wheel 58. 'It will be readily apparent from theforegoing disclosure that rotation of the hand wheel 58 will betransmitted through the shaft 51, the pinion 55, the gear 55, to rotatethe nut 54 and thereby to impart an axial adjustment of the truing toolspindle 26.

In order to hold the nut 54 in adjusted position, a serrated wheel 59 isfixedly mounted on the upper end of the shaft 57. A spring pressed pawl60 mounted on the bracket 5| is arranged to engage the serrated wheel 59and thereby to hold the feed nut 5c in adjusted position.

In order to steady the upwardly extending portion of the feed screw 53,an arm 6| is clamped around a cylindrical surface formed on the upperend of the screw 53 (Figs. 1 and 2). The righthand end of the arm 6| isprovided with a spring pressed ball 52 which rides in a verticallyarranged groove 63 formed in a vertically extending bracket 64. Thebracket 55 is fixedly mounted on the flange 5B of the sleeve 25. It willbe readily apparent from theforegoing disclosure that the arm Bl servesto hold the screw '53 and the spindle 26 against rotary motion butallows a free axial movement thereof.

It is desirable to provide an automatically actuated mechanism forimparting a feeding movement to the truing tool at the ends of itslongitudinal traversing movement. This is preferably accomplished by apawl and ratchet mechanism comprising a ratchet wheel 66 which is keyedto the nut 54 (Fig. 3). A pawl carrier 67 (Figs. 1, 2 and 3) isrotatably mounted on the nut 54 and is provided with a pivotally mountedfeed pawl 58. ihe feed pawl 58 is supported by a stud G9 fastened to thepawl carrier 51. A compression spring Iii serves normally to maintainthe pawl 68 in operative engagement with the ratchet wheel 85. A manualloperable rotatable eccentric 7| (Fig. 2) is provided to facilitaterocking the pawl 88 to an inoperative position if desired so as tofacilitate a manual adjustment of the truing tool spindle 25. Acompression spring '52 normaliy urges the pawl carrier 81 in a clcckwisedirection (Fig, 2) with a stud T3 in operative engagement with a stopsurface 14 which is fixedly mounted on the flange 50 of the sleeve 25.

An automatically operated mechanism is provided for actuating the pawlcarrier 6'1 at the ends of the traversing movement of the truing tool tofacilitate an automatic downward feed of I the pawl carrier 6'? in acounterclockwise 'direction so as to impart a predetermined downwardfeeding movement to the truing tool 28. The ad-' justable dog '15 isadjustably supported by a T- slot 76 formed in the upper surface of thebracket The height of the dogl5 issufiieient' to allow maximum verticalmovementof the spin dle 26 relative to the sleeve'25. I i

The pawl carrier 61 is provided with a'laterally.

extending arm H which supports "a roller ldon a stud 79. The roller 18is arranged in the path of a cam face 85 formed'on an adjustable'dog'fii so that when the slide is approaches the lefthand end of itsstroke, the pawl carrier-61 is rocked in a counter-clockwisedirection'so as to impart a predetermined down feeding movement to thetruing tool 28. The height of the cam face 85 is sufficient to allowmaximum vertical movement of the spindle 26 relative to the sleeve 25.ihe dog 8| is adjustably supported by the T-slot '15. It will be readilyapparent from the foregoing disclosure that 'when the slide i5 traversestoward the right, the pawl carrier 61' will move into engagement withthe dog 15 as the slide approaches the right-hand end of its strokethereby imparting a down feeding movement to the truing tool 28 beforethe .return stroke of the slide 55. Similarly when the slide |3 travelstoward the left, the roller E3 will engage the cam face 85 on the dog 8|as the slide iii approaches the left-hand end of its stroke to impart adown feeding movement of the truing tool 23.

A suitable forming mechanism is provided for generating a predeterminedshape on the periphery of the grinding wheel H3. This mechanism maycomprise a forming bar 85 which is anchored to a bracket 86 by means ofa clamping bolt 87. An adjusting screw 88 serves to precisely adjust theforming bar 35 in a longitudinal direction. The bracket 86 is-fixedlysupported on the fixed bracket l2. The forming bar 85 extends through anelongated slot 89 (Fig. 3)

formed in the sleeve 25 and arranged to slide upon a, slide surface 90formed on the :longitudinally' movable slide I6. A follower 9| isflxedly mounted on the sleeve 25 and is arranged to follow a portion of theform on the bar- 65 during the longitudinal movement of the slide IS ina manner to be hereinafter described.

A. hydraulically operated, lifting mechanism is provided for causing avertical motion of the sleeve 25 to true .a. shouldered portion on thegrinding wheel. This mechanism may comprise a slide bar 95 which isslidably supported on the longitudinally movable slide I6. A follower 96is fixedly mounted on the sleeve 25 and is arranged to be actuated bythe bar 95 whenit is moved longitudinally relative to the slide I6.

The bar 95 is arranged to be traversed longitudinally relative to theslide I 6 by an hydraulically operated mechanism comprising a cylinder Iwhich is fixedly mounted on the slide I6. The cylinder I90 contains asl-idably mounted piston IOI which is connected to one end of a pistonrod 99. The other end of the piston rod 99 is connected to the slide bar95. When fluid under pressure is admitted through a pipe I03 into 'acylinder chamber I02, the piston IOI together with the piston rod 99 andthe slide bar 95 are moved toward the right. During this movement of thepiston IOI, fluid within a cylinder chamber I 04 exhausts throu h a pipeI05, a throttle valve I06 is provided in the pipe line I to regulate therate of exhaust of fluid from the chamber I04 thereby determining therate of longitudinal movement of the slide bar 95. A ball check valve I01 is provided so that when fluid under pressure is passed through apipe I08, it may bypass the throttle valve I06, through the ball checkvalve I01 into the cylinder chamber I04 so that the piston l0I may bemoved toward the left at a relatively fast rate of speed.

A fluid operated control valve I09 is provided to control the admissionto and exhaust of fluid from the cylinder I00. This control valve I09comprising a pilot valve I I0 which is normally held in a right-hand endposition by a compression sprine I I I. A solenoid S2 is provided whichwhen energized serves to shift the pilot valve I I0 toward the left toreverse the flow of fluid so as to shift the control valve I09 into areverse position. The pilot valve IIO serves to control the admission toand exhaust or fluid from a pair of opposed end chambers I I2 and H3 tocontrol thelongitudinal shifting movement of a slidably' mounted valvemember II4.

An hydraulic system is provided for supplying fluid under pressure foractuatin the various parts of the truing apparatus comprising a motordriven fluid pump I50 which draws fluid through a pipe I 5I from a fluidreservoir I52 and forces fluid under pressure through a pipe I53 to thecontrol valves as will be hereinafter described, An adjustable pressurerelief valve I54 is connected in the pipe line I53 to facilitateexhaustins excess fluid under pressure through a pipe. I55 into thereservoir I52.

A fluid operated control valve I25 is provided for controlling theadmission of fluid to the control valve I09. This valve is a piston typevalve comprising a slidablv mounted valve member I26- which is movedendwise by the admission to an exhaust of fluid from end chambers I21and I28 formed at the opposite ends thereof. lhe valve !25 includes apilot valve I29 which is normally held in a right-hand end position by acompression spring I30. A solenoid, S3 is provided,

forshifting the pilot valve I29 toward the left tofacilitate reversingthe position of the slidablymounted valve member I26. In the positionof'the valve I25 (Fig. 5). fluid under pressure pass.- ing, through thepipe I53. may pass through a chamber .I3I in the slidably mounted valvemember I26 and pass out through a pipe I32 to the control valve I09.When the solenoid S3 is energized. the slidably mounted valve member I26is moved toward the right into a right-hand end position which serves tocut off the flow of fluid to the control valve I09 and thereby to cutoff the passage of fluid under pressure to the cylinder I00.

Air-hydraulically operated control valve I35 is provided, forcontrolling the admission to and exhaust of fluid from the cylinder I I.This valve comprises a slidably mounted valve member I36. A pilot valveI3! is normally held in a righthand end position by a compression springI38. A solenoid SI is provided which when energized serves to shift thepilot valve toward the left thereby shifting the valve member I 36toward the right. The pilot valve I31 serves to control the admission toand exhaust of fluid from a pair of end chambers I39 and. I40 formed inopposite ends of the control valve I35. In the position of the valve I35(Fig. 5), fluid under pressure in the pipe I53 passes through a valvechamber MI and through the pipe 24 into the cylinder chamber 23 to causethe piston I8 to move toward the left. Durinsi the movement of thepiston I3 toward the left, fluid within the cylinder chamber 22 mayexhaust through the pipe 2I into a valve chamber I42, through a centralpassage I43 in the valve member I36, through a valve chamber M4 andexhaust through a pipe I45 and a throttle valve I46 into the reservoirI52. The throttle valve I45 serves to control the rate of exhaust offluid and thereby determines the rate of traversing movement of thepiston I0.

It is desirable to provide means for bypassing fluid around the throttlevalve I46 so that the slide I6 may move rapidly during idle portions ofits stroke. This mechanism may comprise a bypass valve I56 which ispreferably a piston type valve comprising a valve stem I51 having a pairof spaced valve pistons I55 and I 59 formed integrally therewith. Acompression spring I60 normally serves to urge the valve stem I51downwardly into the path of a pair of spaced adjustable dogs I GI andI62 which are carried by the slide I6. A pair of fluid pipes I63 and I64are connected to opposite sides of the valve I56 and in the position asshown in Fig. 5 allow fluid to bypass throuah a valve chamber I65 formedbetween the valve pistons I58 and I59 so that unrestricted flow of fluidmay bypass the throttle valve I46 thereby facilitating a rapid movementof the slide I6. It will be readily apparent from the foregoingdisclosure that when the valve stem I51 rides down the slope of the dogI6I, the compression spring I60 will cause a downward movement of thevalve stem l5l so that the valve piston I58 cuts off the passage offluid between the pipes I53 and IE6 thus rendering the bypass valve I56inoperative so that the throttle valve I46 thereafter controls the rateof movement of the slide I6.

A suitable electrical control apparatus is provided for controlling theenergization of solenoids SI, 32 and S3 so as to control the admissionto and exhaust of fluid from the cylinders IT and I00. As illustrated inFigs. 3 and 5, a slide bar I10 is slidably supported on thelongitudinally movable slide I6 in sliding contact with the slide bar95. The slide bar I10 is held in frictional engagement with the slide I6so that the bar 95 may be moved longitudinally by the piston |I withoutmoving the bar I until the lost motion between the adjustable stopscrews Ill and I12 is taken up. The upper surface of the slide bar I10is provided with a plurality of surfaces IIOa, I10b, I100, I10d, I106and Iliif which are arranged in the path of an actuating roller I13 ofthe limit switch LS3.

Another slide bar I15 (Figs. 3 and 5) is slidably supported by the slideI6 and is held in frictional engagement therewith by a friction plateI16 (Fig. 3). The slide bar I15 is arranged so that it moveslongitudinally with the slide I6 until the lost motion is taken upbetween adjustable stop screws I11 and I18, carried by the bar I15 andend surfaces of the slide base I3. of spaced notches I19 and I80 intowhich an actuating roller ISI of the limit switch LS2 may drop as theslide I8 and bar H5 move longitudinally so as to actuate the limitswitch LS2 and thereby to control the energization and deenergization ofthe solenoid S3. The energize.- tion of the solenoid S3 is in partcontrolled by a magnetic switch I85 having a pair of normally opencontactors I86 and I88 and a normally closed contactor I81.

A main control switch I90 is provided for connecting a source ofelectrical energy to the circuit. A manually operable starter switch 59!is provided for starting the truing cycle. Closing of the starter switchI9I serves to energize a mag netic switch I92 and thereby close anormally open contactor I93.

The operation of the improved formed wheel truing apparatus will bereadily apparent from the foregoing disclosure. The main switch I9? isclosed to render the electrical circuits operative. Closing of the mainswitch I90 serves to energize the solenoid S3 so that the valve memberI26 is shifted toward the right thereby cutting off fluid under pressurefrom the pipe I32. The truing cycle may then be started by closing thepush-button starter switch Isl which serves to energize the magneticswitch I92 which sets up a holding circuit. The closing of the starterswitch I9I serves to energize the solenoids SI and S2 which remainenergized during the traversing movement of the slide I6 to the right.Fluid under pressure from the pump I passes through the control valveI35, through the pipe 2| into the cylinder chamber 22 to start movementof the piston I8 and the slide I 6 toward the right. Due to the factthat the bypass valve I56 is opened, the slide I6 and truing tool 28travel first at a relatively fast rate until the follower 9| is about toengage the surface 85a of the template 85 and the truing tool 28 isabout to contact the side face Illa of the grinding wheel Ill. At thistime the valve stem I51 rides down the sloping surface of the dog I6Ithereby cutting off the bypassing of fluid between the pipes I63 and I64so that thereafter the fluid exhausting from the cylinder I1 iscontrolled by the throttle valve I46. Fluid under pressure remainswithin the cylinder chamber 22 during the entire traversing movement ofthe piston I8 toward the right. Engagement of the follower 9| with theside face 85a of the template 85 serves to stop the movement of theslide I8 toward the right with the truing tool 28 in engagement with theside face I0a of the grinding wheel I0.

The slide bar 515 is provided with a pair I When the follower 9| movesinto engagement with the surface a of the template 85, the slide bar I15has shifted longitudinally relative to the slide base I3 so that thestop screw I11 is in engagement therewith. The roller I8I of the limitswitch LS2 rides into the groove I13 thereby shifting the limit switchLS2 to open the upper contacts thereof so as to break a circuit throughcontactor I81 of switch I85 to deenergize the solenoid S3 so that fluidunder pressure may pass through the pipe I32, through the control valveI09, through the pipe IE8 into the cylinder chamber I02 to cause thepiston IOI to move toward the right at a speed governed by the throttlevalve I06. Movement of the piston IOI toward the right causes acorresponding movement to be imparted to the slide bar 95. During theinitial movement of the slide bar 95, the slide bar I10 remainsstationary until the stop screw I1I moves into engagement with theleft-hand end thereof. As the slide bar moves toward the right, thefollower 95 moving up the inclined surface 951) of the slide bar 95imparts a vertical movement to the sleeve 25 so that the follower 9|rides up the side face 85a of the template 85 and the truing tool 28moves upwardly along the side face Illa of the grinding wheel I9 to truethe same. When the slide bar I10 moves toward the right, the roller I13swings in a counterclockwise direction to actuate the limit switch LS3thereby energizing the magnetic switch I85. As the follower 5| reachesthe radius [01) of the grinding wheel It, the pressure within thecylinder chamber 22 moves the piston I8 toward the right and the shapeof the template 85 controls the vertical movement of the follower 9| togenerate the radius I01) on the grinding wheel I0 and also the formedsurface I0c i generated by the follower Si riding up the surface 850 ofthe template During the movement of the slide bar 65 toward the right tomove the surface 950 into the position illustrated in Fig. 6, the rollerI13 rides along the notch I10b maintaining the limit switch LS3 with theupper contacts closed to maintain the magnetic switch I85 energizeduntil the roller I13 engages the inclined surface I which serves toshift the limit switch LS3 into the position illustrated in Fig. 5thereby opening the circuit to the coil of the magnetic switch I85. Theroller IiII is in engagement with the notch I19 of the slide bar I15 sothat the lower contacts of the limit switch LS2 are closed therebysetting up a holding circuit to maintain the magnetic switch I85energized and the solenoid S3 deenergized. The solenoid S3 remainsdeenergized until the piston I0! again moves and actuates the limitswitch LS3 to energize magnetic switch I85. During the latterlongitudinal movement of the piston I 8 and the slide I6 toward theright, the roller |8I rides out of the notch I19 to shift the limitswitch LS2 into the position illustrated in Fig. 5 so a to energize thesolenoid S3 after the generation of the surface We on the wheel I0.

When the follower 9| approaches the shoulder 85d on the template 95 andthe truing tool 28 approaches the shouldered face I0d on the grindingwheel I0, the roller I 8| drops into notch I80 on the slide bar I15thereby shifting the limit switch LS2 to deenergize the solenoid S3 sothat the control valve I25 may again pass fluid under pressure throughthe pipe I32 to the control valve I09. Fluid under pressure passes fromthe control valve I09 through the pipe I03 to again -move the piston- IItoward the right. This movement causes a corresponding movementrto theright of theslidebar 95 so thatthe-follower 96 slides upwardlydue-to-thesloping surface 95d on the slide bar 9-5 to raise the sleeve25"andthe truing tool 28 in a vertical direction to true the shoulderedface lildon the grinding'wh eel ID as the follower SI rides uptheshoulderedface 85d onthe template 85.- The upward movement of thefollower 96 and truing'tool 28 continues until the fol-lower -96 israised onto the portion "95c andthe follower 9l' h'aspassed partiallyaroundthe'radi-us 85c on the -template 85 so that the truing tool 28'ispartially around the-radius 'IOeof the grinding wheel I0.- At'this pointfluid under pressure within the cylinder *chamber- 22 .until the slideI6 engages and opens the normally closed limit switch LS4 which servesto break the holding circuit thereby deenergizing the magnetic switchI92. Breaking the circuit and deenergizing switch I92 also serves :todeenergize the sole- .noids Sl and S24. thereby shifting the-:controlvalves I35 and I09 respectively into the positions illustrated in Fig. 5where they remain during the return traversing stroke of the piston I8and slide I6 toward the left. The operation of the follower relative tothe template 85 together with the controls above described operate in asimilar manner on the traversing movement toward the left to again passthe truing tool across the face of the grinding wheel. Prior to thereturn stroke of the truing tool, the dog engages the pawl carrier 61and rocks it in counterclockwise direction. This movement serves throughthe pawl 88 and the ratchet wheel 66 to impart a down feeding movementto the truing tool 28before the truing tool starts its return traversetoward the left. Similarly as the piston I8 and slide I6 approach theleft-hand end of the traversing stroke, the roller "I8 rides up the camface 80 of the dog BI to again impart a down feeding movement to thetruing tool 28 so that it is positioned for the next truing operation.

It will thus be seen that there has been provided by this invention agrinding wheel truing apparatus in which the various objects hereinaboveset forth together with many thoroughly practical advantages aresuccessfully achieved. As many possible embodiments may be made of theabove invention and as many changes might be made in the embodimentabove set forth, it is to be understood that all matter hereinbefore setforth or shown in the accompanying drawings is to be interpreted asillustrative and not in a limiting sense.

I claim:

1. In a grinding wheel truing apparatus having a slide base, alongitudinally reciprocable slide thereon, a transversely movable truingtool carrier on said slide, a truing toollthereon, means including apiston and cylinder on said base to traverse said slide longitudinally,means including a follower on said carrier which operativelyengages-aiaforming baron saidislide to-impart a controlled transversemovement to the truing tool carrier during longitudinal movementoftheslide, means including a longitudinally movable cludinga cylinder onsaid slide, a-sli'dable piston therein :whichis operatively-connected tosaid cam-to'm-ove said cam longitudinally-relative-to said slide; saidfirst follower and forming bar serving to hold said slide stationaryduring --movement of said cam and control means includinga control valvemechanism operatively connected tea-both of said cylinders alternatelyand successively-to traverse said slide longitudinally -and to traversesaid cam, longitudinally-relative to theslide to generate apredeterminedcontour grinding wheel. 2;;In a grinding wheel truing apparatus havingabase, a longitudinally reciprocable slide, a transv on. theoperativenface of. a

versely movable truingtool carrier, on said, slide, a

truing tool 'adjustably mounted on; said carrier,

- means including afolloweron said carrier which operatively engages a,forming bar on saidslide to impart a controlled transverse movement tothe twins 1 r i ri rine. lon itud nal. mov m oftheslide, acyliride tonsaid baSe @piStonsI-idab n d; h reicwhichr s. re i rely-co nally, meansincluding ed. o i s i eto,traver eth -slid lon itud a longitudinallymovable cam on said slide which engages a follower on said carrier toimpart a transverse movement to the truing tool carrier when the slideis stationary to true a shouldered face on a grinding Wheel being trued,a cylinder on said slide, a piston slidable therein which is operativelyconnected to said cam to actuate said cam, and control means including acontrol valve mechanism operatively connected to both of said cylindersalternately and successively to traverse said slide longitudinally andto traverse said cam longitudinally relative to the slide so as togenerate a predetermined contour on the operative face of a grindingwheel.

3. In a grinding wheel truing apparatus having a base, a longitudinallyreciprocable slide thereon, a transversely movable truing tool carrieron said slide, a truing tool adjustably mounted on said carrier, aforming bar fixedly mounted relative to the base, a follower on saidcarrier which engages said forming bar to facilitate generating apredetermined shape on a peripheral portion of a grinding wheel beingtrued, means including a cylinder on said base, a piston slidabletherein which is operatively connected to said slide to traverse saidslide longitudinally, a longitudinally movable cam on said slide, asecond follower on said carrier in operative engagement with said cam,means including a cylinder on said slide, a piston slidable thereinwhich is operatlvely connected to said 0am to move said camlongitudinally relative to said. slide to cause a transverse movement ofthe carrier relative to the slide to facilitate truing a side face or ashouldered face on a grinding wheel being trued, said first follower andforming bar serving to hold theslide stationary during a transversemovement of the carrier for shoulder or side truing,

and control means'including a control valve mechanism 0-perativelconnected to both of said cylinders intermittently to traverse saidslide longitudinally and to traverse said cam longitudinally relative tosaid slide to generate a predetermined contour on the operative face ofa grinding wheel.

4. In a grinding wheel truing apparatus having a base, a longitudinallyreciprocable slide thereon, a transversely movable truing tool carrieron said slide, a truing tool adjustably mounted on said carrier, afollower on said carrier and a forming bar which is engaged by saidfollower and is fixedly mounted relative to the base to facilitategenerating a predetermined shape on a portion of the operative face of agrinding wheel, a cylinder on said base, a piston slidable therein whichis operatively connected to said slide to reciprocate said slide, meansincluding a follower on said carrier and a longitudinally movable cam onsaid slide to facilitate a transverse movement of the carrier for sideor shoulder truing, a cylinder on said slide, a piston slidable thereinwhich is operatively connected to said cam to traverse said camlongitudinally relative to said slide, and electrically-controlledhydraulically-actuated mechanism operatively connected to both of saidcylinders intermittently to traverse said slide longitudinally and totraverse said cam relative to said slide to generate a predeterminedcontour on the operative face of a grinding wheel.

5. In a grinding wheel truing apparatus, as

claimed in claim 4, in combination with the parts and features thereinspecified of a solenoid-actuated control valve operatively connected tosaid 'slide cylinder to control the admission to and exhaust of fluidfrom the slide cylinder, a second solenoid-actuated control valveoperatively connected to said cam actuating cylinder to control theadmission to and exhaust or fluid from the cam actuating cylinder, athird solenoid-actuated control valve operatively connected to saidsecond valve to control the admission of fluid to said second valve, amagnetic switch operatively connected to said third valve to actuatesaid third valve, means including a cycle start switch operativelyconnected to the first and second valves to energize the first andsecond valves to initiate a truing cycle, means including a switch onsaid slide which is actuated by and in timed relation with thelongitudinal movement of said cam to energize said magnetic switch andthe third valve to cause a transverse movement of the carrier for a sideface or shoulder grinding operation.

OIVA E. HILL.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,171,516 Alvord Sept. 5, 1939 2,248,463 Ott July 8, 19412,302,854 Granberg Nov. 24, 1942 2,433,027 Casella Dec. 23, 19472,576,570 Castelll Nov. 27, 1951 FOREIGN PATENTS Plumber Country Date536,300 Great Britain May 9, 1941

